Mesoscale Discussion 1240
   NWS Storm Prediction Center Norman OK
   0217 PM CDT Sat Jul 10 2021

   Areas affected...much of Oklahoma...southeast Kansas...and northwest
   Arkansas

   Concerning...Severe potential...Watch likely 

   Valid 101917Z - 102115Z

   Probability of Watch Issuance...80 percent

   SUMMARY...Thunderstorms will develop this afternoon and evening
   across the region. Large hail and damaging winds will be the primary
   threat, although a tornado or two cannot be ruled out. A watch will
   likely be needed by 4 PM CDT.

   DISCUSSION...A surface cold front across southwest Kansas is slowly
   moving southeast this afternoon with an effective stationary front
   extending from south-central into northeast Kansas. Along and south
   of this frontal zone, diurnal heating has contributed to a very
   unstable airmass as surface temperatures warm into the mid 80s F to
   lower 90s F with surface dewpoints in the low-to-mid 70s F. As this
   heating continues, surface-based inhibition will erode and several
   clusters of thunderstorms will develop. Initial development --
   likely before 21Z -- should occur across eastern Kansas within the
   aforementioned frontal zone, with additional development later this
   afternoon farther southwest across Oklahoma.

   Surface-based CAPE in excess of 3000 J/kg, mid-level lapse rates
   between 7 and 8 C/km, and effective-layer shear between 40-50 knots
   will combine to support thunderstorms capable of large hail and
   damaging thunderstorm wind gusts. Given the degree of instability
   and effective-layer shear, a tornado or two will be possible with
   thunderstorms, especially early in their life cycle when they remain
   more discrete and may pose supercellular characteristics. With time,
   congealing thunderstorm cold pools and outflows will promote upscale
   growth into one or more south-southeast moving linear MCSs, with the
   primary severe hazard transitioning to more of a widespread wind
   damage potential.

   A watch will likely be needed across portions of this area by
   21Z/4PM CDT.

   ..Marsh/Bunting.. 07/10/2021

   ...Please see www.spc.noaa.gov for graphic product...

   ATTN...WFO...LZK...SGF...TSA...ICT...OUN...DDC...

   LAT...LON   35409937 37139858 37809734 38039598 37989467 37869429
               36479369 35409376 34699587 34619926 35409937